Search results for query: t slot

...to an .026 you will start the booster later. At that point you start getting a bigger gap in the time between the near (later) end of the T slot and getting on the booster. Under certain conditions you may have to start the PV a bit sooner (higher number) so when the booster does come on and...

This happened to me once and it ended up being a reverse polarity at the pick-up coil. This sent the ECU into a dither and it couldn't figure out exactly when to fire. Funny thing is it would idle just fine. The strobe only went whacky when the rpm began to rise. Quick question; Why are you...

The T-slot position in post #57 is PERFECT.

...Air mixture screws 2 1/2 turns out Idle timing 10* BTDC Idle speed screw out 1.5 turns from throttle valve seated. (shows a little t slot. Looks like 3 turns gives approx .030 exposure) So, how would I increase idle timing and/or T slot exposure without getting the idle RPM up too high...

Not sure I’d get too caught up on the the small transfer slot exposure. Mine idles at 950 in park with very little t-slot exposed. I would suspect air is coming from somewhere else, or as RRR mentioned timing.

...idle....goes in the same fairy tale book as the PV on a Holley opening at idle & causing richness. Neither is possible IF the throttle blade/ t slot position is correct. The reason is that there is insufficient air flow past the almost closed blades; insufficient air flow means not enough...

You may need to redefine your perfromance goals. Its hard to know what you mean by good. I define them as a best power and efficiency for the condition. We can judge this objectively for most steady state conditions. There's some links in this post that I think will be useful as they provide...

...number of 2.5 turns comes from. The number of turns will be whatever provides the smoothest idle. What is imperative is that 0.020-0.040" of t slot is exposed at the desired idle speed with the correct idle timing. This is how the carb is designed to operate & provide the correct see-saw...

...have TWO problems. [1] Just adding a little throttle to move the car [2] When you stab the throttle. [1] Remove the carb & check how much T slot is showing below the blades 0.020 - 0.040" is ideal. If NONE showing it indicates an air leak OR this carb has bypass air holes; these could be...

...start. It’s insane running all that emulsion. Edit: you can lower the IFR. That helps with idle a bunch. Also, a .035 is pretty big. You may end up in the .076-.078 idle air bleed range. That’s not always a bad thing unless you run out of idle circuit and T slot before it gets on the...

...read all the benefits of a curve........but proof is proof. So THAT theory, for me, is put to bed. Period. My next effort is concerning T slot restrictors. As posted earlier, I went down to .062 all 4 corners and it made a pretty good improvement. I am still a wee bit rich at cruise around...

i'm ordering this kit tonight as i'm installing the fbo ignition box and flamethrower coil i got tomorrow. this engine really didn't like any sort of advance at all but im hoping i can get some satisfaction out of the limiter plate. right now ive got a t bar ive just welded in the slots to lock...

Your new heads probably have larger intake port volume, which reduces velocity AND carb signal. This explains your symptoms. Getting leaner when hot does not sound right.....expect it be leaner when cold. What: - idle vacuum - idle timing - idle rpm - t/slot position - carb

...you are on the booster at 2800 then you need to drop the primary main jet to get the cruise AFR where it needs to be. If you are still on the T slots, I'd drop down to .048ish. If you get on the lean side of it the next time you swap in some brass you can always just pull them back out and...

...closed off....& never had a problem. Many TQs & AVS carbs had bypass air holes in the base which can be blocked/reduced in size to correct the T slot position. The problem with T slots is when there is too much exposed at idle. PCV can be run from front or rear of carb, whichever is more...

I occasionally like to drive it hard. I bought the afr meter to get most out of the new carb. And if I could get better fuel mileage that would be a bonus. Im aware that afr meter might show falsely reading in idle with big cam overlap. I tuned idle mixture with vacuum gauge to get maximum...

A. I read post 1 again. I come up with the cam being 6* retarded, not 4*. Idle vac will be very low, performance poor. It would also explain lack of detonation with a lot of timing. It also explains why the engine needs a lot of ign timing, plugs being sooty from low vac/t-slot open too far...

...at idle'. Only if there is a manufacturing fault where the mixture screws do not seat against their seats.....& that would be rare. If the T slot position is correct, screwing in the mixture screws will stall or almost kill the engine from lack of fuel. The idle fuel feed is sized to provide...

Great post

Carb is a 6139. I guess I'll revisit these questions when the actual 340 is on the stand. I just figured that I could get some insight on the current curve, and TQ characteristics using the "mule" 318 as a test pilot. At least the 340 should run good enough to break in with this combo...

In case of IFR my understanding is that these restrictors deliver only gas so they can be rather small. In my case t-slot restrictor was not allowing the engine to pull right amount of gas in the transition slot which resulted in very lean condition.

...[ with the extra timing ], a smoother idle with more vacuum than what you had using less timing. It is also ok if you have less than 040" of T slot at idle. I have never found it to cause a problem, & it leaves more of the T slot available to cover from idle to the mains cct. I am betting...

...I COULD jet down a bit further and enlarge the PVRC. After much reading and listening to you guys, I think I need to put restriction in my T slot channels instead. So that's what I'm going to try. It would be a band aid fix (I think), to have 74 jets up front and 82's in the back. I'm...

Chevy, no wonder you have no clue.

Not knowing much I’d say you need T slot restricters. Not sure what you have for emulsion but some of those carbs came with too much emulsion and way too big of a main air bleed. A bigger air bleed wi start it on the booster sooner. If your MAB is bigger than .026 it’s probably too big. That...

Listen, I know you're a smart man, but if you can't then neither can OP. So then, for the OP; as to 25*, this is easy, just tug on the distributor until the Idle speed no longer increases, and that is what she likes. and as to Idle timing: Take the carb off. Set the T-slot exposure to square...

If the carb is calibrated for a PCV, and you install it in such a way that the PCV is not able to function, then in order for the engine to idle, the speed screw will need to be cranked quite a bit higher, for the engine to get the missing PCV air. Of course cranking in the speed-screw, will run...

...Sometimes the fix will be a combination of two or more things, such as more timing + more fuel. But, yes, remove the carb to check where the T slots are. Here is a trick to check the T slot position without removing the carb every time: - adjust idle screw so that 0.020" slot is showing...

I have no idea why people that have no clue what they are saying state such easily debunked dribble. Here is a photo from the book written by Cliff Ruggles on how to modify Rochester Carburetors for high performance use. Book is called How to Rebuild & Modify Rochester Quadrajet Carburetors...

Cam is a Hughes 3844 (237º/243º@ .050" 108ºLSA). Installed straight up 'per Hughes recommendation. Cam card numbers matched my degree wheel numbers within 1/2º, so there does not seem to be anything 'ground in' to the cam. Now now...it's in my sig. A833. Holley 4779. Yes. 4-corner idle...